On May 1st, 2000, the US Government disabled a feature within its Global Positioning System (GPS) called Selective Availability (SA).
GPS includes a (currently disabled) feature called Selective Availability (SA) that adds intentional, time varying errors of up to 100 meters (328 ft) to the publicly available navigation signals. This was intended to deny an enemy the use of civilian GPS receivers for precision weapon guidance.
On May 3, 2000, civilian, Dave Ulmer hid a bucket of swag here and posted the coordinates on the internet, creating the first official geocache. Since then over a million caches have been hidden. The city of Mt Holly has found over 250 of them.